The present invention relates to a locking system, in particular a locking system for aircraft landing gears according to the description herein, and to a method for operating a locking system for an aircraft.
Nowadays, modern aircraft mostly have hydraulic retractable landing gears. To ensure their air worthiness, in particular in high-speed flight, it is necessary that in operation the landing gear systems of such aircraft can safely be retracted, held and, if necessary, for instance during a landing operation, can just as safely be extended again.
Safely holding has so far been realized by locking systems which are mechanically connected with the structure of the aircraft and in the retracted condition of the landing gear system make a positive connection with the same. Such system is shown for instance in FIG. 1.
Only in the course of an externally activated hook opening movement is the landing gear system positively released and extended either hydraulically or by the acting gravitation. Due to the relatively high reliability requirements for such systems, the external activation of the hook opening movement now is achieved primarily by a hydraulically actuated piston and secondarily by a mechanical cable actuation or by an electromechanical actuating unit.
The cable systems of such mechanical actuating units frequently must be guided through the fuselage of the aircraft via pressure or temperature zones, deflection pulleys, guideways and distributors. What is disadvantageous here is the complex assembly, intensive maintenance and the varying cable tension due to different material properties in the system. FIG. 1 shows such locking system for an aircraft. In the course of an externally activated hook opening movement, the landing gear can positively be released. Among other things, the hook opening movement can be activated mechanically by a cable system. The cable systems must be guided over a plurality of deflection pulleys and guideways, which is very expensive and also susceptible to failure.
Furthermore, locking systems with electromechanical actuating units are known from WO 2005/005252 A1. The same are realized by means of an electromagnetic coil or an electric motor with spindle or the like. Here, it is disadvantageous that the same cannot always be returned to the starting condition by simply shutting off the energy supply and are not capable of a reset/restart in any condition.